U.S. Pat. No. 5,935,039 and Tokkai Hei 10-220551 published by the Japanese Patent Office in 1998 disclose infinite speed ratio transmission devices for a vehicle wherein a fixed speed ratio transmission and a planetary gear set are combined with a toroidal continuously variable transmission (CVT) in order to increase the speed ratio range of the CVT.
In each of these devices, an engine output is input into the CVT and the fixed speed ratio transmission. The output shaft of the CVT is joined with a sun gear of the planetary gear set, and the output shaft of the fixed speed ratio transmission is joined with a planet carrier of the planetary gear set via a power circulation clutch. A ring gear of the planetary gear set joined to a final output shaft of the transmission device drives the wheels. The output shaft of the CVT is also joined to the final output shaft of the transmission via a direct clutch.